The first commercial preparation of hyaluronic acid, Synvisc became available in Canada in 1992. Since then, we have injected many arthritic joints, with Synvisc, NeoVisc, and Suplasyn. The relief of pain is variable, we usually state 75% of patients have pain relief with minimal adverse effects. At the present time we are using Suplasyn.
Viscosupplements work best in early osteoarthritis (OA) or in knees that fail to improve after arthroscopy. In the joint, hyaluronate provides viscoelasticity (lubrication) of synovial fluid and resilience (cushioning effect) to the cartilage. It is unlikely viscosupplements will work where joint malalignment or bone on bone situations exist.
Viscosupplementation is also beneficial after arthroscopic debridement of the knee or after microfracture of cartilage lesions.
The injections must be intra-articular. Intra-synovial or extra-articular injections will not work and are much more likely to product inflammatory reactions. The incidence of local reactions can vary depending on the product injected, but is typically 1-2%. Occurrence of transient pain at the injection site is the most common reaction.
Presently, there are several different products available for injection – however the source of hyaluronic acid varies. NeoVisc, Suplasyn, Duralane, Orthovisc and Hyalgan GF 20 or synvisc are the products presently approved for use in Canada. With the exception of NeoVisc and Suplasyn, all other products are extracted from rooster combs and a contraindication to treatment would be an allergy to eggs or chicken. Durolane and Synvisc are high molecular weight products.
Most available viscosupplements consist of three prepackaged syringes containing 2mL each. One injection is given per week for three to 5 weeks. Onset of symptomatic relief varies depending on the severity of OA. Effects last an average of 6 to 12 months.
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